The present invention relates to an oscillating belt sander/spindle sander, and more particularly, to a combined motor and mechanical drive for transmitting rotational and reciprocating motion to an output motor shaft end which is constructed to facilitate conversion between an oscillating belt sander or spindle sander, as may be desired.
In my aforementioned co-pending patent application Ser. No. 08/233,278 filed Apr. 26, 1994, now U.S. Pat. No. 5,549,507, a combined motor and mechanical drive is disclosed that provides simultaneous rotary and reciprocating or axial movement of an output motor shaft for use with an oscillating spindle sander or the like. With a spindle sander sleeve attached to the output motor shaft, the spindle sander sleeve reciprocates or oscillates at a speed much slower than it rotates. Typically, the spindle sander sleeve rotates at 1725 rpm while moving up and down in an oscillating movement approximately 60 times per minute over a range of approximately 3/4". This dual rotary and oscillating movement allows the spindle sander to remove a large amount of material from a wood workpiece in a very rapid manner without creating scratch patterns that are characteristic of a conventional drum sander. For both rough shaping and final finish sanding, this combined up and down and around movement is very helpful.
Following development of the aforementioned rotating and oscillating movement for spindle sanders, it was discovered that belt sanders could also favorably employ a rotating sanding belt that would reciprocate or oscillate, as well. Sanding results similar to the aforementioned spindle sanders could thus be favorably achieved.
In developing such belt sander, it was discovered that the combined motor and mechanical drive, disclosed in aforementioned co-pending patent application Ser. No. 08/233,278 filed Apr. 26, 1994, now U.S. Pat. No. 5,544,507, could also be usefully employed. To maximize use of the combined motor and mechanical drive for spindle sanders as well as belt sanders, it was further discovered that the output motor shaft of the combined motor and mechanical drive could be constructed and/or arranged to facilitate interchangeable mounting of a spindle sander to a belt sander. Thus, the same combined motor and mechanical drive could be employed for use with an interchangeable mounting system to facilitate conversion from a spindle sander to a belt sander.
While some prior art developments, notably U.S. Pat. No. 4,939,870 and European Patent Application No. 060862582, have disclosed the desirability of using the same drive for use with a belt sander or spindle sander, no prior art device has considered the adaptability and performance of the aforementioned combined motor and mechanical drive for a spindle sander or belt sander. Moreover, no prior art device has considered the use of simple and practical conversion devices that can be employed for converting a spindle sander to a belt sander, as will be apparent from the discussion that follows.